Materials Literature
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We study the quantum forces that act between two nearby conductors due to electronic tunneling. We derive an expression for these forces by calculating the flux of momentum arising from the overlap of evanescent electronic fields. Our result is written in terms of the electronic reflection amplitudes of the conductors…
Taking into account stress fluctuations due to thermal noise, we study thermally activated irreversible crack growth in disordered media. The influence of material disorder on sub-critical growth of a single crack in two-dimensional brittle elastic material is described through the introduction of a rupture threshold…
We report measurements of the optical responses of a La2∕3Sr1∕3MnO3 (LSMO) sample at a wavelength of 533 nm in the 300–400 K range. At 335 K the temperature coefficient of the resistance of a 100-μm-wide, 300-μm-long LSMO line was 0.017K−1 and the normalized Hooge parameter was 9×10−30m3, which is among the lowest rep…
Photoinduced electron transfer is a widely applied method to convert photon energy into a useful (electro)chemical potential, both in nature and in artificial devices. There is a continuing effort to develop molecular systems in which the charge-transfer state, populated by photoinduced electron transfer, survives suf…
Inorganic nanoparticles with controlled size and shape seem especially technologically important due to the strong correlation between these parameters and their magnetic, electrical, and catalytic properties. Herein we demonstrate that uniform spinel cobalt oxide (Co 3 O 4 ) nanocubes can be successfully synthesized…
Four discrete MnIII/MnII tetra-nuclear complexes with double-cuboidal core were synthesized. dc magnetic measurements show that both Mn2+ - Mn3+ and Mn3+ - Mn3+ magnetic interactions are ferromagnetic in three samples leading to an S = 9 ground state for the Mn4 unit. Furthermore, these complexes are Single-Molecule M…
We present the structures of putative global potential energy minima for clusters bound by the Stockmayer (Lennard-Jones plus point dipole) potential. A rich variety of structures is revealed as the cluster size and dipole strength are varied. Most remarkable are groups of closed-loop structures with the topology of k…
In the present work we theoretically analyze the effect of the Fermi surface local geometry on quantum oscillations in the velocity of an acoustic wave travelling in metal across a strong magnetic field. We show that local flattenings of the Fermi surface could cause significant amplification of quantum oscillations.…
The dependence of superlattice thermal conductivity on period length is investigated by molecular dynamics simulation. For perfectly lattice matched superlattices, a minimum is observed when the period length is of the order of the effective phonon mean free path. As temperature decreases and interatomic potential str…
We present a new phase mask coronagraph consisting in an optical vortex induced by a space-variant surface relief subwavelength grating. Phase mask coronagraphy is a recent technique aiming at accommodating both high dynamic and high angular resolution imaging of faint sources around bright objects such as exoplanets…
In recent years layered double hydroxides (LDHs), also known as hydrotalcite-like materials, have attracted considerable interest from both industry and academia. In this article, we discuss methods of preparing LDHs with an emphasis on the way in which particle size and morphology can be controlled with regard to spe…
Arrays of gold split rings with a 50-nm minimum feature size and with an LC resonance at 200 THz frequency (1.5 microm wavelength) are fabricated. For normal-incidence conditions, they exhibit a pronounced fundamental magnetic mode, arising from a coupling via the electric component of the incident light. For oblique…
Magnetic excitations in the quasi-one-dimensional antiferromagnet IPA-CuCl3 are studied by cold neutron inelastic scattering. Strongly dispersive gap excitations are observed. Contrary to previously proposed models, the system is best described as an asymmetric quantum spin ladder. The observed spectrum is interpreted…
An optimal solubility screen is described that uses the results of crystallization trials to identify buffers that improve protein solubility and, in turn, crystallization success. This screen is useful not only for standard crystallization experiments, but also can easily be implemented into any high-throughput struc…
Peptide amphiphiles combine the specific functionality of proteins with the engineering convenience of synthetic amphiphiles. These molecules covalently link a peptide headgroup, typically from an active fragment of a larger protein, to a hydrophobic alkyl tail. Our research is aimed at forming and characterizing cova…
Supercritical CO 2 was used to produce CaCO 3 thin films on biopolymers such as cellulose and chitosan coated on glass substrates from aqueous solutions of calcium acetate and poly(acrylic acid) (PAA). The scanning electron microscopy (SEM), X-ray diffraction (XRD), and energy-dispersive X-ray (EDX) results suggest th…
Whereas eubacterial and eukaryotic riboflavin synthases form homotrimers, archaeal riboflavin synthases from Methanocaldococcus jannaschii and Methanothermobacter thermoautrophicus are homopentamers with sequence similarity to the 6,7-dimethyl-8-ribityllumazine synthase catalyzing the penultimate step in riboflavin bi…
Three FeII complexes, [Fe(HLR)2](BPh4)2.solvent (R=H, Me, Ph), were synthesized, where BPh4-=tetraphenylborate and HLR=2-substituted-imidazol-4-yl-methylideneamino-2-ethylpyridine. The magnetic susceptibility measurements in 5-300 K revealed that [Fe(HLH)2](BPh4)2.H2O, [Fe(HLMe)2](BPh4)2.2CH3CN, and [Fe(HLPh)2](BPh4)2…
Pulsed plasma polymerization of N-isopropylacrylamide leads to the deposition of thermoresponsive films. The reversible (switching) behavior of these poly(N-isopropylacrylamide) surfaces has been exemplified by screening the adsorption of fibrinogen and fluorescein isothiocyanate labeled bovine serum albumin proteins…
In this work, isolated fine silver nanoparticles and polypyrrole/silver nanocomposites with diameters of about 10 nm on gold substrates were first prepared by electrochemical methods. First, an Ag substrate was cycled in a deoxygenated aqueous solution containing 0.1 M HCl from −0.30 to +0.30 V versus Ag/AgCl at 5 mV/…